Speech transmitter for masks



March 4, 1947. c. r. MORROW SPEECH TRANSMITTER FOR MASKS Filed Jan. 17, 1946 2 Sheets-Sheet l March 4, 1947.

C. T. MORROW SPEECH TRANSMITTER FOR MASKS Filed Jan. 17, 1946 2 Sheets-Sheet 2 Patented Mar. 4, 1947 2,416,939 SPEECH TRANSMITTER FOR MASKS Charles T. Morrow, Cambridge, Mass, assignor to the United States of America, as represented by the Executive Secretary of the Office oi Scientific Research and Development Application January 17, 1946, Serial N 0. 641,826

This invention relates to a mask and has for its objects the provision of a simple and effective mask outlet valve which permits easy breathing; another object is to provide improved acoustic performance of masks so that speech may be more eifectively transmitted. Other objects will appear from the following description.

In the accompanying drawings:

Fig. l is a side elevational view of the gas mask of the invention;

Fig. 2 is a plan cross section taken along the plane 2-2 of figure 1;

Fig. 3 is a plan view;

Fig. 4 is a detail elevational view of one elementof the mask;

Fig. 5 is another detail View of the element shown in Fig. 4;

Fig. 6 is a plan view showing a development of another element of the mask;

Fig. 7 is a detail cross sectional view;

Fig. 8 is another plan cross section;

Fig. 9 is a perspective view of still another element of the mask;

Fig. 10 is an elevational view illustrating the mask as viewed from its inner side; and

Fig, 11 is a plan View.

Referring more in detail to the drawings, [0 denotes a facepiece or covering in which is fastened valve means generally indicated by the arrow I2 and through which the breath may be expelled. The valve means includes a V-shaped outer plate; a V-shaped diaphragm; a diaphragm support; a valve seat structure; and fastening means.

The outer plate is indicated by numeraI I4 and consists of two semi-annular sections through 1 Claim. (01. 128-141) which are formed openings Hi to permit passage of air. Located adjacent to the inner sides of the plate I4 is a flexible diaphragm l8 of rubberized cloth (Fig. 9), which generally conforms to the shape of the plate I4. The diaphragm proper is supported in a framework 19 of relatively thick rubber of similar material. Numeral ll denotes a vertically extendin valve portion. Against the inside of the diaphragm memberis located a diaphragm support 20 which is also shaped to conform to the contour of the diaphragm and plate l4, and similarly is provided with air passages 22.

Seated against the valve portion I1 is a triangularly-shaped valve seat structure 24, which is adjustably secured by one or more balls 26 resiliently clamped in position by one or more hasps 28.

The valve seat 24 is formed along two sides with openings 38, as may be more clearly seen from an inspection of Figs. 4 and 5. The upper end of the triangular valve seat terminates at a point just below the facepiece IE3, and the lower end of the valve seat likewise terminates at a point inside of the lower portion of the iacepiece, preferably in a tubular extension 34, which may include a flapper valve 32. The valve seat, by the bail and hasp arrangement shown, may be easily dropped back out of position to permit cleaning or other operations. The lower end of the valve seat pivots with the tubular extension.

Attention is directed to Fig. 2 in which it will be noted that the triangular valve seat structure is illustrated in partial cross section with the corner portions of the triangular member lying in close contact with the valve portion ll of the diaphragm member [8. In operation, the operator exhales and the breath passes through the openings 22 in the plate member 26]. The pressure of the breath forces the thin rubber diaphragm l8 outwardly, temporarily lifting the valve portion I! away from the triangular valve seat structure 24, thus opening a passageway which connects with the openings 3!] in this member. The breath passes into the valve seat structure and down through it, escaping at the bottom of the tubular extension 34. The diaphragm member is supported against its diaphragm support 20 as air is inhaled from a canister or other air conduit, with the valve portion remaining closed.

An important feature of the arrangement described is ease of exhalation. Very little pressure is required to displace the diaphragm and open the valve portion, and thus the lung muscles are protected from premature fatigue. Another important aspect of the invention is improved speech transmission resulting from the relatively large diaphragm area and particular space provisions which are possible with this type of valve member.

Another important feature of the valve means is the elimination of conventional valve arrangements which tend to cause injury to the face in case of the wearers falling. In the valve means of the invention the force of impact in case of falling would be distributed over a large area with resultant protection. With the arrangement of the invention, it becomes possible to use conveniently a telephone handset, an operation which could not be successfully carried out with the older type of valve means.

It is intended that the invention may be subject to various changes and modifications. For example, the back of the valve seat structure may 3 be modified to include a stop member to assist in positioning the hasp member. Similarly, the hasp may be modified to include an opening through which the stop member may project when the hasp is in an engaged position.

While I have shown a preferred embodiment of my invention, it *should be understood that various changes and modifications may be resorted to, in keeping with the spirit of the invention as defined by the appended claim.

Having thus described my invention, what I claim is:

An article of the character described, comprising a facepiece casing, plate means tightly secured in sealed relation in the casing, said plate consisting of two semi-annular portions bent into a V-shaped member, a diaphragm element of a shape corresponding to that of the'plate, said diaphragm including a relatively thick framework, a triangularly shaped tubing detachably clamped against the framework and-having openings formed 'therethrough, said diaphragm normally lying in sealed relation to the openings 4 in the triangularly shaped tubing to form a valve, a diaphragm support member located inside of the diaphragm, said diaphragm support having openings formed therethrough for the passage of the breath, said diaphragm being adapted to be urged outwardly upon exhalation, providing a passageway through the openings-in the triangular valvemember and thus forming an exhaust channel.

CHARLES T. MORROW.

REFERENCES CITED The following references are of record in the file of this patent? UNITED STATES PATENTS Number Name Date 2,410;4'54 'Motsin'ger Nov. 5, 1946 FOREIGN PATENTS Number Country Date soaoso V Britis'h Jan.'2'9,."1929 

